Surah 7. Al-A'raf

91This defeat and acknowledgment turned the tables on the people of Pharaoh. They had mustered all the expert magicians of the land to demonstrate publicly that Prophet Moses was a magician or, at least, to create doubts in the minds of the public about his Prophethood. But after the defeat, their own experts in the art admitted unanimously that what Prophet Moses was presenting was not magic at all, but most surely it was the work of the power of the Lord of the worlds, and that every kind of magic was powerless against it.

Obviously their considered opinion could not be brushed aside in an offhand way, for none could judge magic better than the magicians. That is why when the magicians testified, after practical demonstration and trial, that it was not magic, it became impossible for Pharaoh and his courtiers to assert that Moses . was a magician.